A vibration motor has been used as a vibration generation means, which is one of the most significant features of an electronic device such as a mobile phone, the motor with an eccentric axis or an unbalanced center of gravity being rotated to generate vibration. However, the vibration motor has many problems that a brush passes through interpolar regions between segments during the rotation of the motor, causing friction and sparks, which leads to a shorter lifespan.
A linear vibrator has been developed to solve the aforementioned problems of the vibration motor. The linear vibrator suffers from less friction and abrasion than the vibration motor because a vibrator mounted on a spring vibrates in an up-down or left-right linear motion due to an electromagnetic force between magnets and a coil. In addition, the linear vibrator can be produced in a smaller size, so developed in various forms.
FIG. 1 is a view showing an example of a conventional linear vibrator. As disclosed in Korea Registered Patent Publication No. 10-1434554, a horizontal linear vibrator includes a bracket 10, a casing 20, a coil 12, a vibration body 30, a housing 40, and an elastic member 51. The elastic member 51 of the conventional linear vibrator shown in FIG. 1 includes a rectangular horizontal plate 53 having a certain volume, a pair of plate springs 51c′ formed in a V shape, integrally bent at both side front and rear ends of the horizontal plate 53 in opposite directions, respectively, with a sectional shape of ‘’ and ‘’, and elastically deformed in the horizontal direction in the form of a cantilever, respectively, and a pair of horizontal welding fixing plates 52a integrally bent on the respective end top and bottom surfaces of the plate springs 51c′ toward the horizontal plate 53 to secure the upper and lower ends of the plate springs 51c′ to the ceiling surface of the casing 200 and the top surface of the bracket 10 by the welding, respectively.
However, in the conventional linear vibrator, the plate springs 51c′ of the elastic member 51 disposed at both sides of the vibration body 30 located at the center are provided in the diagonal direction, so the restoring forces of the plate springs 51c′ of the elastic member 51 are not applied to the center of the vibration body 30 but to the edges of the vibration body 30, as indicated by the red arrows of FIG. 1. Accordingly, some minute rotational force may occur on the vibration body 30, causing undesired irregular motion, as a result of which the bracket 10 and the vibration body 30 may interfere with each other and disadvantageously reduce vibration performance or stability.